The Duomo CO2 Monitor & Controller is designed to monitor the level of CO2 as well as room temperature and humidity in applications such as offices, classrooms and kitchens.   It provides an optional on/off relay output to operate a ventilation system. The unit has an audible alarm and a three colour backlit 'traffic light' style switching alarm display.   The backlight is green under normal conditions and is set to change at 1000ppm to amber and at 1400ppm to red. This and other features of the unit can be customised to meet your exact requirements before shipment.   The controller also has an optional RS485 communication interface to connect directly to a building management system as part of your complete system.